Bergman, Patrick

Abstract [en]

Introduction

Natural environments are known to promote health and may also provide extraordinary conditions for post exercise recovery (Kuo 2015). In the project Health Effects of Recreation Outdoors (HERO) we explore the hypothesis that post exercise recovery in natural environments may be reflected in white blood cell counts (WBC). In our study 50 seniors (age >65 years) performed moderate physical activity (20 min) followed by passive recovery (2h) in three different environments (indoors, simulated outdoors and “true” outdoors).

Method

The experimental setup was a randomized cross-over design, thus all test persons did all treatments in a randomized order. We sampled white blood cells (WBC-diff), which were used to detect and quantify inflammatory response.

Results

Our early findings provide some support for the hypothesis that environment may impose differences in recovery effectiveness. White blood cell count (WBC-diff) appears to differ between the treatments and there is a significant interaction between sampling time and recovery environment in the monocytes, suggesting that the monocyte numbers differ, not only between sampling times but also between environments. In addition, WBC also show that some of the test persons develop leukocytosis during exercise and that white blood cell levels decrease rapidly immediately post exercise to levels significantly lower than base line values.

Discussion

Our results suggest that moderate physical activity in senior citizens may result in acute leukocytosis (see e.g. Sand et. al. 2013) and that recovery effectiveness (e.g in monocyte response) may be dependent upon environmental factors. The clinical importance of our results are not fully understood but there has been suggested an “open window” immediately post exercise in which infection risk may be elevated (Pedersen & Toft 2000) and it is possible that recovery out of doors may reduce this risk.